The ACCENT R Host Language Interface (HLI) is a set of procedures that allows a 3GL (3rd Generation Language) program to access the Data Set (DS) objects and Data Index (DI) objects within an ACCENT R Data Base Library (DBL). The functionality of 3GL (3rd Generation Language) programs can be combined with the power of ACCENT R using a surprisingly few number of routines to master. Existing applications do not have to be re-written to take advantage of the capabilities of ACCENT R. This manual describes how the ACCENT HLI application programming interface functions on VAX/OpenVMS.
The HLI overcomes many of the shortcomings of conventional 3GL file access, with features such as:
Data items are identified by name. The physical position of each item within each record and the format of the records (ASCII, BINARY) need not be known by the host program. Thus, the program becomes much less dependent on data organization.
Up to 511 different record types may be defined in a single file. The sizes of each record type need not be the same. The record type need not be known before the record is read.
ACCENT R DB-MACH2's Data Index objects may be used for flexible random access processing.
Compatibility with all ACCENT R DB-MACH2 file types allows the HLI to access existing ACCENT R databases without conversion.
Many users can simultaneously access and update the same files with either record or file level locking controlled by ACCENT R DB-MACH2.
The following assumptions have been made in this section:
The reader is familiar with COBOL, FORTRAN, or C and has written at least one program that uses procedures.
The reader is familiar with VAX/OpenVMS user commands.
The reader is familiar with ACCENT R and has defined and used ACCENT R Data Index objects.
The HLI's capabilities include:
Up to 30 Data Set objects can be read or updated simultaneously by the HLI.
System COBOL, FORTRAN, and C procedure libraries can be used with the HLI. For example, these libraries might include:
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